Tuesday, 12 January 2010

Calvert White-winged Gulls

Having been more or less house-bound for more than a week now due to the snow the only birding I'd done had been slogging through the snow on Port Meadow. On the Meadow I'd discovered that there were still some birds to be seen along the river and the Mill Stream, a small side stream with the highlights having been a water rail scurrying away in the undergrowth and a few redshank and snipe along the river banks. As the roads were becoming passable again I thought that I would venture out a bit further and with a first winter glaucous gull having been seen at the BBOWT reserve at Calvert the previous day I thought that I would have a crack at that.

I'd been worried about the state of the road leading up to Calvert but it turned out that it had been recently gritted and swept so it was in reasonable condition and I arrived at the parking area at around 2:30pm. A quick look in the first hide revealed the lake amazingly to be almost entirely ice free with just the far bank fringes iced over. There were lots of gulls dotted all round the lake so I made my way to the second hide from which there is a better view of the whole area. I started scanning through the birds looking for the coffee colouring of a first winter glaucous. In passing I noted a flock of 14 red-crested pochards in the middle of the lake, doing an interesting head nodding display which looked rather comical. As I continued scanning I noticed what appeared to be a white winged adult gull swimming in the water. I tracked it for a while and it eventually reached the ice fringe where it got out and started grooming. At that point I started doing some video recording as it did look interesting but the hide was constructed so the floor boards kept vibrating up and down so I soon had to stop and adjust my tripod to try to minimise the bounce. I did a bit more recording, made some more adjustments but then couldn't find the bird again. I had been a bit confused by what appeared to be a dark band below the white primaries. Puzzled as to what exactly it had been I resumed scanning through the flock and soon afterwards found the glaucous gull which I spent some time trying to photograph though it was a good distance away and there was very little light. Very pleased with having connected with the glaucous gull and not wanting to get too caught up in the rush-hour traffic I soon left and managed to get home shortly after 4pm

Several glaucous gull shots
A wing flap of the glaucous gull
Some of the red-crested pochard flock with a yellow-legged gull in front of them

The next morning I was going through my photos and I remembered the mysterious white-winged gull that I'd seen so I made a couple of grabs and had a look. It seemed to have some pale grey marks along the primaries so I started to wonder about a Kumlien's gull though I was still a bit confused by the dark line beneath them: was this a partially hidden black primary - I just didn't have the experience. I spoke with Ian Lewington about the bird and he explained that the dark line is the coalescing of a number of darker feather tips beneath the outermost primaries. He also said on first inspection that he thought the bird was good for a Kumliens though after the ID was queried by others I asked him to take another look and after he'd had time to consider it fully at it he agreed that actually it was a herring gull with unusually pale (perhaps partially melanistic) primaries. Apparently the mantle colour was too dark and the bird not delicate-looking as an iceland gull is. Still an interesting bird and a fine example of what a minefield gull identification can be if even someone such as Ian can be fooled on first inspection.

A grab of the mystery gull - a herring gull not a Kumlien's gull as I'd hoped

Another grab of the bird

The video footage of the mystery gull

I'd been pleased just to see the glaucous gull and the ID tussle concerning the possible Kumlien's had been most interesting. My more leisurely-paced year list is ticking along albeit at a rather sedate rate: I've managed to miss the Otmoor bittern fest and the Piddington swan fest already but in my non-county year listing mode I'm concentrating more on quality than quantity this year.

National & Oxon Year List 2010
046 dunnock 04/01/2010 Garden
047 bullfinch 04/01/2010 Garden
048 mute swan 05/01/2010 Port Meadow
049 mistle thrush 05/01/2010 Port Meadow
050 wren 05/01/2010 Port Meadow
051 golden plover 05/01/2010 Port Meadow
052 tufted duck 05/01/2010 Port Meadow
053 skylark 05/01/2010 Port Meadow
054 snipe 05/01/2010 Port Meadow
055 coal tit 07/01/2010 Garden
056 song thrush 07/01/2010 Garden
057 grey heron 08/01/2010 Port Meadow
058 goosander 08/01/2010 Port Meadow
059 water rail 08/01/2010 Port Meadow
060 common gull 08/01/2010 Port Meadow
061 blackcap 10/01/2010 Garden

National Year List 2010
062 pochard 11/01/2010 Calvert, Bucks
063 RC pochard 11/01/2010 Calvert, Bucks
064 glaucous gull 11/01/2010 Calvert, Bucks
065 Yellow-Legged gull 11/01/2010 Calvert, Bucks

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